In readying KDE 4.12 for release next month, the second beta of the KDE 4.12 applications and platform packages are now available for early adopters and those testing this leading desktop environment...

What the heck are they doing:
They wanted to phase out 4 and concentrate pushing for kde-5

Will this be like enlightenment, where you have to mask higher versions to get the new?

The current work right now is with a new generation of KDE libraries, called "frameworks 5". However, KDE 4 libraries and KDE frameworks 5 libraries can live side-by-side, and applications written for KDE 4 libraries will run just fine in a frameworks 5-based workspace. So the library developers are busy getting frameworks 5 ready, but applications developers are still release kdelibs4 applications, and can continue to do so after frameworks 5 is released next summer. This will allow applications to switch over when they are ready, rather than having everything switch over at once as happened with KDE 4.0.